Welcome back to our exploration of time! In “Part I”, we have presented the current time zone system and the International Date Line (IDL). Even with that understanding, a compelling question remains: why cannot the entire world simply share a single unified time zone? This concept seems appealing, especially when we consider that in reality it is up to each country or region to decide what time zone it should be in, and if they want to switch to Daylight Saving Time, for example. In this article, we delve deeply into these fascinating concepts, meticulously examining their potential advantages and the challenges they would introduce.
Daylight Saving Time
Several countries adjust their clocks forward and backward by an hour during the year for Daylight Saving Time (DST). You may perceive this practice as “cheating”, but it is actually a common global practice that yields several benefits. Shifting clocks forward throughout the summer helps save energy, due to potential less reliance on artificial lighting during longer daylight hours, thereby reducing electricity consumption. Furthermore, it gives people more daylight in the evening, allowing more time for outdoor activities and recreation.
It is essential to note that the DST is not a globally standardized practice, and the transition dates differ across nations. Egypt, for example, currently observes summer time between the last Friday in April and the last Thursday in October, to avoid potential time-related issues or disruption to governmental operations during normal workdays. According to the DST law, the clock is set a one-hour forward in spring and a one-hour backward in autumn.
Messing up with our bedside clocks, not to mention our internal clocks, can be inconvenient, especially when losing an hour of sleep in the spring; yet, the extended summer evenings are often considered worthwhile. Conversely, you wake up feeling more rested in autumn, as you gain an extra hour of sleep. Although some people may feel deeply frustrated for one or two days a year, would you imagine doing this every day and for longer hours a day?
A Unified Time Zone
The experience of waking up at 7:00 am to total darkness that would last for three or four more hours is not merely a thought; it is a reality for people living in countries that have chosen a unified time zone across their borders—China and India are prominent examples. Let us have a closer look into a global similar scenario; imagine a world where the time is perfectly unified, perhaps set to match time in Cairo. Now, picture someone on the opposite side of the globe; it is now 7:00 pm according to our universal clock, but the Sun would be merely rising, or it is noon, the brightest part of the day, but it is total darkness there. Frustrating, is not it?
This quick setting reveals the fundamental reason for time zones; a global time would be completely disconnected from the natural rhythms of day and night across the planet. You may think people would get used to that, but science has indeed a different opinion on the necessity of one’s connection to the natural world. Implementing a single global time would lead to:
- Messing up with Our Biological Clocks: all living organisms, including humans, possess an internal cardician clock that regulates the body’s functions, largely in sync with the cycle of day and night. Travelers, for example, experience “jet lag” when rapidly crossing multiple time zones; their bodies struggle to adjust to the new light-dark cycle. A unified time zone would essentially force a perpetual state of jet lag for a significant portion of the world’s population without even traveling. When the clock says it is time to sleep, while there is still daylight, the body’s natural signals based on its circadian clock are contradicted. A study conducted on India, concluded that operating under a single time zone can cause sleep deprivation in children and adults, and affect overall health and well-being.
- A Social Jet Lag: While a single time zone might seem to simplify scheduling, it would become incredibly awkward for working schedules, school start times, and generally the organization of social time. Experiencing “noon” at your location, is to know that someone thousands of miles is simultaneously experiencing a vastly different stage of the day’s light. This coordination process would become a chaotic endeavor, causing what chronobiologists—scientists studying biological rhythms, periodic changes in physiological and behavioral functions of living organisms—refer to as “social jet lag”, which means a discrepancy arising between biological and social rhythms. A “forced synchronization” can have harmful effects on health and economic productivity.
- Loss of Fundamental Concepts: the Sun’s position in the sky dictates our clocks and it is not the same everywhere. The Earth’s relationship to the Sun defines the very concepts of “morning”, “afternoon”, and “night”, which would lose their inherent meaning and become arbitrary labels. A single global time would also fundamentally alter our perception of hours, days, and years, as they would no longer consistently align with the solar cycle in our specific location. The relationship between time, the Sun’s position, and location, are essential in disciplines as astronomy, navigation, meteorology, and climatology.
Before the invention of time zones, long before the advancement of various means of transportation and travelling far, each place had its own local time based on the position of the Sun in its sky. While the idea of a single global time zone might sound simple, it would introduce other complexities. Despite their variations, time zones have coordinated our life in terms of communication, business, and travel, and facilitated our daily activities by respecting our biological rhythms and preserving our connection to nature.
References
bbc.co.uk
earthobservatory.nasa.gov
learningresources.com
livescience.com
momatos.in
oceanservice.noaa.gov
pacioos.hawaii.edu
sciencemuseum.org.uk
timeanddate.com (1)
timeanddate.com (2)
Cover image by Freepik